CVE-2020-11996

A specially crafted sequence of HTTP/2 requests sent to Apache Tomcat 10.0.0-M1 to 10.0.0-M5, 9.0.0.M1 to 9.0.35 and 8.5.0 to 8.5.55 could trigger high CPU usage for several seconds. If a sufficient number of such requests were made on concurrent HTTP/2 connections, the server could become unresponsive.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
tomcat8	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	23.10 mantic	Not in release
	23.04 lunar	Not in release
	22.10 kinetic	Not in release
	22.04 LTS jammy	Not in release
	21.10 impish	Not in release
	21.04 hirsute	Not in release
	20.10 groovy	Not in release
	20.04 LTS focal	Not in release
	19.10 eoan	Not in release
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not in release
tomcat9	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	21.04 hirsute	Not affected
	20.10 groovy	Not affected
	20.04 LTS focal	Fixed 9.0.31-1ubuntu0.1
	19.10 eoan	Ignored end of life
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release

Notes

mdeslaur

HTTP/2 support introduced in 8.5

Severity score breakdown

Parameter	Value
Base score	7.5 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

USN-4596-1
Tomcat vulnerabilities
21 October 2020